Publication and writing of 10 blog posts on DA 20+ websites

We are looking to build our backlinks for some of our keywords. We want to get 10 for each word and it may be of interest to have the blog posts written for us depending on the price.
We sell promotional products so marketing and business blogs would be of interest but we also wouldn't mind other blogs that focus on universities, construction, trade shows, small businesses, cosmetics and other industry specific blogs.
We would provide the topic of the blog posts that are written for us and would like to read before being published.